ROS1 Nodelet Updates

[marip8]

This PR adds the following updates:

• Fixes topic remapping for the ScanToCloudFilterChain nodelet
  • In the current implementation, any topic remapping applied to the nodelet is ignored because the ScanToCloudFilterChain class uses its own public node handle, not the public node handle provided by the nodelet which accounts for topic remapping
• Adds a nodelet implementation for the ScanToScanFilterChain class
  • This class was also updated to accept public and private node handles from the nodelet to account for topic remapping correctly

Addresses #71

[jonbinney]

Looks like a nice improvement! I just need to do a code review before I merge.